使用填充将整数转换为字符串

#include <stdio.h>
#include <limits.h>

#define MAXLINE 1000

void itoa(int n, char s[], int w);
void reverse(char s[]);

int main(void){
    char s[MAXLINE];
    int width;

    width = 11;
    itoa(INT_MIN, s, width);
    printf(%12d is converted to %s.\n, INT_MIN, s);
    itoa(123, s, width);
    printf(%12d is converted to %s.\n, 123, s);
    itoa(-321, s, width);
    printf(%12d is converted to %s.\n, -321, s);

    return 0;
}

void itoa(int n, char s[], int w){
    int i = 0, sign= n, remainder, k, j;

    do {
        remainder = n % 10;
        s[i++] = ((sign < 0) ? -remainder : remainder) + '0';
    } while (n /= 10);
    if (sign < 0)
        s[i++] = '-';

    while (i < w)
        s[i++] = ' ';

    s[i] = '\0';
    reverse(s);
}

void reverse(char s[]){
    int tmp;
    int j = 0;
    for (j = 0; s[j] != '\0'; ++j)
        ;
    --j;

    for (int i = 0; i < j; ++i, --j) {
        tmp = s[i];
        s[i] = s[j];
        s[j] = tmp;
    }
}